From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-3.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id B8DB4C4321D for ; Mon, 20 Aug 2018 05:15:06 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 77F2521534 for ; Mon, 20 Aug 2018 05:15:06 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 77F2521534 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=suse.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726383AbeHTI3M (ORCPT ); Mon, 20 Aug 2018 04:29:12 -0400 Received: from mx2.suse.de ([195.135.220.15]:39102 "EHLO mx1.suse.de" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1725944AbeHTI3L (ORCPT ); Mon, 20 Aug 2018 04:29:11 -0400 X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay2.suse.de (unknown [195.135.220.254]) by mx1.suse.de (Postfix) with ESMTP id 19D25AD48; Mon, 20 Aug 2018 05:15:02 +0000 (UTC) From: Juergen Gross To: linux-kernel@vger.kernel.org, xen-devel@lists.xenproject.org, x86@kernel.org Cc: boris.ostrovsky@oracle.com, hpa@zytor.com, tglx@linutronix.de, mingo@redhat.com, Juergen Gross Subject: [PATCH 1/2] x86/xen: don't write ptes directly in 32-bit PV guests Date: Mon, 20 Aug 2018 07:14:55 +0200 Message-Id: <20180820051456.20779-2-jgross@suse.com> X-Mailer: git-send-email 2.13.7 In-Reply-To: <20180820051456.20779-1-jgross@suse.com> References: <20180820051456.20779-1-jgross@suse.com> Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org In some cases 32-bit PAE PV guests still write PTEs directly instead of using hypercalls. This is especially bad when clearing a PTE as this is done via 32-bit writes which will produce intermediate L1TF attackable PTEs. Change the code to use hypercalls instead. Signed-off-by: Juergen Gross --- arch/x86/xen/mmu_pv.c | 7 +++---- 1 file changed, 3 insertions(+), 4 deletions(-) diff --git a/arch/x86/xen/mmu_pv.c b/arch/x86/xen/mmu_pv.c index 9e7012858420..9396b4d17064 100644 --- a/arch/x86/xen/mmu_pv.c +++ b/arch/x86/xen/mmu_pv.c @@ -434,14 +434,13 @@ static void xen_set_pud(pud_t *ptr, pud_t val) static void xen_set_pte_atomic(pte_t *ptep, pte_t pte) { trace_xen_mmu_set_pte_atomic(ptep, pte); - set_64bit((u64 *)ptep, native_pte_val(pte)); + __xen_set_pte(ptep, pte); } static void xen_pte_clear(struct mm_struct *mm, unsigned long addr, pte_t *ptep) { trace_xen_mmu_pte_clear(mm, addr, ptep); - if (!xen_batched_set_pte(ptep, native_make_pte(0))) - native_pte_clear(mm, addr, ptep); + __xen_set_pte(ptep, native_make_pte(0)); } static void xen_pmd_clear(pmd_t *pmdp) @@ -1569,7 +1568,7 @@ static void __init xen_set_pte_init(pte_t *ptep, pte_t pte) pte = __pte_ma(((pte_val_ma(*ptep) & _PAGE_RW) | ~_PAGE_RW) & pte_val_ma(pte)); #endif - native_set_pte(ptep, pte); + __xen_set_pte(ptep, pte); } /* Early in boot, while setting up the initial pagetable, assume -- 2.13.7